Different kinds of sensors serving as user interfaces in devices, such as mobile devices, are known in the art for sensing an input action of a user. In touch sensors, the input is performed via touching a sensor surface with a finger or stylus. Therefore, touch sensors provide a user interface or man-machine interface to control various functions of the device having the touch sensor incorporated therein.
Known touch sensors work by reacting to a change in capacitance affected by the presence of a finger or a stylus of a user. The position sensing capability can be achieved by providing two layers with capacitive components in the touch sensor. These components are connected with each other horizontally in the first layer and vertically in the second layer to provide a matrix structure enabling to sense a position in x,y-coordinates of where the touch sensor is touched. In capacitive touch panels, a capacitive component of one layer forms one electrode of a capacitor and the finger or stylus forms another electrode.
In other touch sensors having a capacitive ITO pattern each sensor element consists of two electrodes. One connected to the controller and one connected to ground. When a finger is present the coupling is effected between ground electrode and top electrode and thus effecting the voltage.
For example, the so-called CapTouch Programmable Controller for Single Electrode Capacitance Sensors AD7147 manufactured by Analog Devices, Norwood, Mass., USA (see data sheet CapTouch™ Programmable Controller for Single Electrode Capacitance Sensors, AD7147, Preliminary Technical Data, 06/07—Preliminary Version F, 2007 published by Analog Devices, Inc) may be used to measure capacitance.
Recent applications, such as multi-touch applications, require that more than one position on a touch sensor is touched and sensed, e.g. to determine a section of an image on a display that is to be magnified or to trigger a specific function.
Since touch sensors are usually placed on top of a liquid crystal display (LCD), large parts of the sensor have to be made transparent, which can be achieved by manufacturing the touch sensor of transparent capacitive components.
Therefore, it is desirable to provide a touch sensing device, touch screen device, mobile device, method for sensing a touch and method for manufacturing a touch sensing device allowing various kinds of input operations.